Synthesis of highly luminescent and photo-stable, graded shell CdSe/Cd xZn1-xS nanoparticles by in situ alloying

Abstract

We report a facile and robust synthesis of CdxZn1-xS graded shells on CdSe nanoparticles that are prepared by interface alloying between CdS and ZnS shells at elevated temperatures. Alloying provides systematic control over the electronic structure and enables switching between Type-I and quasi-Type-II configurations. Good control of particle shape, shell thickness, and composition is achieved by slowly adding zinc oleate and octane thiol via syringe pump to readily prepared CdSe/CdS particles. The resultant quantum dots exhibit PL quantum yields of up to 97% and superior robustness toward environmental influences and quenching agents. Alloying promotes a blue-shift of both the absorption an..